Communication Signal Receiver for Estimating an Imaginary-Part Component of a Complex Data Signal and Method Thereof

1. A communication signal receiver for estimating an imaginary-part component of a complex data signal, comprising: a feed-forward filter, for receiving a real-part component of the complex data signal and for generating an estimated imaginary-part component signal according to the real-part component of the complex data signal by using tap coefficients of the feed-forward filter; a first coefficient adjusting circuit, coupled to the feed-forward filter, for adjusting the tap coefficients of the feed-forward filter according to a control information, wherein the control information at least comprises a phase error information, and the phase error information changes as a phase of the complex data signal adjusted or not adjusted by the first coefficient adjusting circuit changes; a delay unit, for delaying the real-part component of the complex data signal to generate a delayed real-part component signal; and a phase error corrector, coupled to the delay unit and the feed-forward filter, for adjusting a complex phase corresponding to the delayed real-part component signal and the estimated imaginary-part component signal according to the phase error information.

2. The communication signal receiver of claim 1 , wherein the control information further comprises at least one of a signal quality information corresponding to the complex data signal and a channel lock status information.

3. The communication signal receiver of claim 1 , wherein the phase error corrector comprises: a look-up table, for providing a sine value and a cosine value according to the phase error information; and a complex multiplier, for adjusting the complex phase corresponding to the delayed real-part component signal and the estimated imaginary-part component signal according to the sine value as well as the cosine value.

4. The communication signal receiver of claim 1 , further comprising: a feed-back filter, for receiving a designated signal and for generating a filtered designated signal according to the designated signal by using tap coefficients of the feed-back filter.

5. The communication signal receiver of claim 4 , further comprising: a second coefficient adjusting circuit, coupled to the feed-back filter, for adjusting the tap coefficients of the feed-back filter according to the control information.

6. The communication signal receiver of claim 4 , wherein the tap coefficients of the feed-back filter is a predetermined value.

7. The communication signal receiver of claim 4 , further comprising: an operator, coupled to the feed-forward filter and the feed-back filter, for adjusting the estimated imaginary-part component signal according to the filtered designated signal.

8. A method for estimating an imaginary-part component of a complex data signal, comprising: generating an estimated imaginary-part component signal according to a real-part component of the complex data signal together with a group of feed-forward filtering tap coefficients; adjusting the group of feed-forward filtering tap coefficients according to a control information, wherein the control information at least comprises a phase error information, and the phase error information changes as a phase of the complex data signal adjusted or not adjusted by a coefficient adjusting circuit changes; delaying the real-part component of the complex data signal to generate a delayed real-part component signal; and adjusting a complex phase corresponding to the delayed real-part component signal and the estimated imaginary-part component signal according to the phase error information.

9. The method of claim 8 , wherein the control information further comprises at least one of a signal quality information corresponding to the complex data signal and a channel lock status information.

10. The method of claim 8 , wherein the step of adjusting the complex phase corresponding to the delayed real-part component signal and the estimated imaginary-part component signal according to the phase error information comprises: providing a sine value and a cosine value according to the phase error information; and adjusting the complex phase corresponding to the delayed real-part component signal and the estimated imaginary-part component signal according to the sine value as well as the cosine value.

11. The method of claim 8 , further comprising: generating a filtered designated signal according to a designated signal by using a group of feed-back filtering tap coefficients.

12. The method of claim 11 , further comprising: adjusting the group of feed-back filtering tap coefficients according to the control information.

13. The method of claim 11 , wherein the group of feed-back filtering tap coefficients is a predetermined value.

14. The method of claim 11 , further comprising: adjusting the estimated imaginary-part component signal according to the filtered designated signal.

15. The method of claim 14 , wherein the step of adjusting the estimated imaginary-part component signal according to the filtered designated signal comprises: subtracting the filtered designated signal to generate the estimated imaginary-part component signal.

16. A communication signal receiver for estimating an imaginary-part component of a complex data signal, comprising: a feed-forward filter, for receiving a real-part component of the complex data signal and for generating an estimated imaginary-part component signal according to the real-part component of the complex data signal by using tap coefficients of the feed-forward filter; a feed-back filter, for receiving a designated signal and for generating a filtered designated signal according to the designated signal by using tap coefficients of the feed-back filter; an operator, coupled to the feed-forward filter and the feed-back filter, for adjusting the estimated imaginary-part component signal to generate an operated estimated imaginary-part component signal according to the filtered designated signal; a delay unit, for delaying the real-part component of the complex data signal to generate a delayed real-part component signal; and a phase error corrector, coupled to the delay unit and the operator, for adjusting a complex phase corresponding to the delayed real-part component signal and the operated estimated imaginary-part component signal according to a phase error information, where the phase error information changes as a phase of the complex data signal changes; wherein both the tap coefficients of the feed-forward filter and the tap coefficients of the feed-back filter are adjusted by the phase error information.

17. The communication signal receiver of claim 16 , wherein the phase error corrector comprises: a complex multiplier, for adjusting the complex phase corresponding to the delayed real-part component signal and the operated estimated imaginary-part component signal according to a sine value as well as a cosine value.